Dual-Band Circularly Polarized Aperture-coupled Stack Antenna with Fractal Patch for WLAN and WiMAX Applications

This article presents a novel circular polarized (CP) aperture coupled stack antenna for wireless local area network and worldwide interoperability for microwave access dual-band systems. The compact stack antenna consisted of square fractal patch, aperture couple, feed line and the perturbation. The square patch is constructed with the complementary Minkowski-island-based fractal geometry. By way of adjusting the relevant parameters, we can obtain the dual-band responses at 3.5 and 5.25 GHz respectively. The CP of each band are presented. The measured 10 dB return loss impedance bandwidth are 270 MHz (7.5%) for 3.5 GHz band and 450 MHz (8.6%) for 5.25 GHz band. The 3 dB axial ratio bandwidths for each bands are 1.4 and 0.76%, the polarization of radiation patterns are both left-hand CP, and the antenna power gain are 2.84-3.1 and 0.16-2.2, dBic respectively. The proposed antenna is successfully simulated and measured with frequency responses, radiation patterns and current distributions. (c) 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:130-138, 2014.